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OK, got the caps ordered from Digi-Key today. Will hopefully get here for next weekend.
Checks of the 3 section "Candohm" resistor (R117) were showing a couple open sections, so I desoldered and removed it. Sure enough, both the 850 ohm and one of the 650 ohm sections were intermittently open, coming and going when I pressed on a couple of the lugs. But strangely enough, after wiggling all the lugs, the connections now seem rock solid, and all sections test OK, even when pressing and prying at it. Does anyone have an opinion as to whether this thing should be reinstalled? Was considering hooking it up to a power supply to heat things up to see if the fix is permanent or not.
If I do replace it, what would be the recommended modern equivalent, and how to mount it? The unit consists of a separate 850 ohm 12W section, and 2 650 ohm 6W units with a center tap between them. I immediately thought of the standard square wirewounds, but presumably the candohm was used to get the heat dissipation onto the outside of the chassis, rather than underneath. Maybe some of those fancy aluminum cased screw mount jobs?
There was a thin layer of fiber insulation board (almost certainly asbestos-based) that was between the chassis and the aluminum resistor mounting plate, presumably to keep some of the heat from soaking into the chassis wall. It was very carefully removed (soaked down with water/detergent to prevent dust), and will be replaced with a modern fiberglass based material.
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